science

Vaccine-induced seropositivity

Vaccine-induced seropositivity is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Vaccine-induced seropositivity rather than just read about it. In short: Vaccine-induced seropositivity (VISP) is the phenomenon wherein a person who has received a vaccine against a disease would thereafter give a positive or reactive test result for having that disease when tested for it, despite not actually having the disease. This happens because many vaccines encourage the body to produce antibodies against a particular disease, and blood tests often determine whether a person has…

Key takeaways

Vaccine-induced seropositivity belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Vaccine-induced seropositivity to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Vaccine-induced seropositivity from memory before moving on to harder problems.

Reference excerpt

Vaccine-induced seropositivity (VISP) is the phenomenon wherein a person who has received a vaccine against a disease would thereafter give a positive or reactive test result for having that disease when tested for it, despite not actually having the disease. This happens because many vaccines encourage the body to produce antibodies against a particular disease, and blood tests often determine whether a person has those antibodies, regardless of whether they came from the infection or just a vaccination. VISP is especially a concern in vaccine trials for HIV vaccine research because people who give a positive result in an HIV test, even if that result is because of a vaccine and not because of an infection, may face discrimination because of HIV infection.

HIV

Background In 1987 in America the first HIV vaccine was tested. HIV vaccines have been tested continually worldwide since then, but thus far, no one has developed any vaccine which reduces a person's risk of contracting HIV if exposed to that virus. Many HIV tests work not by checking a person's blood for HIV, but rather by determining whether the body's own antibodies against HIV are present in the blood. Most HIV vaccines are designed with the intent to promote the body's own production of antibodies which would combat HIV. Regardless of whether they are effective at stimulating the production of antibodies which fight HIV, they usually do cause the body to produce antibodies which standard HIV tests recognize as the antibodies which an HIV positive person would produce in response to HIV infection. A person who is HIV negative, and has received an HIV vaccine, and who then tests as positive in an HIV test is said to be positive because of VISP.

Significance When an HIV-negative person exhibits VISP and gets an HIV-positive result from a test then that person may have difficulty donating blood or negotiating for a life insurance policy. Between 1987 and 2003 the number of persons who received experimental HIV vaccinations was about 10,000, and this number was considered small. The difficulties in determining the difference between antibodies produced by HIV infection and vaccine-induced antibodies were managed by individual vaccine research sites who had special capability to conduct additional laboratory testing on this small pool of vaccine recipients. However, at this time two new studies, the STEP Study in the US and the RV 144 study in Thailand, greatly increased the number of people who received HIV vaccinations by another 4600 people. There came to be an increased need to raise awareness of VISP because more people were exhibiting it. At the 2010 International AIDS conference presenters talked about the need for community healthcare providers to understand that if their patients have been in an HIV vaccine trial then their patients are likely to give a false positive HIV test result.

HIV VISP in developing countries HIV vaccine research happens worldwide to ensure that any vaccine which researchers develop could be used for people worldwide. In developing countries with limited access to healthcare, the problems associated with VISP are a special concern. Researchers from Africa, Asia, North America, and South America have said that getting local government and media support of the research is essential in addition to creating facilities for distinguishing between HIV positive individuals and individuals exhibiting VISP.

Likelihood People who participate in vaccine trials which test HIV vaccines may exhibit VISP for years or for the rest of their lives. A study done on participants in the HIV Vaccine Trials Network HIV vaccination studies showed that among 2176 HIV negative participants who received a vaccine, 908 (42%) had VISP. However, the occurrence of VISP varied depending on what kind of vaccine the participants received.

Hepatitis B When a person gets a hepatitis B vaccine then the most common test for hepatitis B will show them to be positive. The usual course of action, in this case, is to give the person a panel of tests for HBsAg, anti-HBc, and anti-HBs (hepatitis B surface antigen, anti-hepatitis B core, and anti-hepatitis B surface). A person who has never been exposed to hepatitis B but has gotten the vaccine will be positive for anti-HBs but negative for the other two tests in the panel. Other combinations of positive and negative in this test can mean other things, such as acute, chronic, or past infection.

Other conditions VISP is not often a practical concern for other diseases because in most cases good vaccines already exist and most people who have access to healthcare receive them. Also physicians do not routinely test people for recent infections with most diseases as they do for HIV. Medical literature on VISP for most diseases is not widely available because there is little practical need for doing that research.

References

Surender Khurana, Needham J, Mathieson B, Rodriguez-Chavez IR, Catanzaro AT, Bailer RT, Kim J, Polonis V, Cooper DA, Guerin J, Peterson ML, Gurwith M, Nguyen N, Graham BS, Golding H. Human Immunodeficiency Virus (HIV) Vaccine Trials: a Novel Assay for Differential Diagnosis of HIV Infections in the Face of Vaccine-Generated Antibodies. J. Virol. (2006); 80(5): 2092–99./> Surender Khurana, Needham J, Park S, Mathieson B, Busch MP, Nemo G, Nyambi P, Zolla-Pazner S, Laal S, Mulenga J, Chomba E, Hunter E, Allen S, McIntyre J, Hewlett I, Lee S, Tang S, Cowan E, Beyrer C, Altfeld M, Yu XG, Tounkara A, Koita O, Kamali A, Nguyen N, Graham BS, Todd D, Mugenyi P, Anzala O, Sanders E, Ketter N, Fast P, Golding H. HIV-SELECTEST, A Novel approach for differential diagnosis of HIV infections in the face of vaccine generated antibodies: Utility for detection of diverse HIV-1 subtype. JAIDS (2006); 43(3): 304–12./> Surender Khurana, Norris PJ, Busch MP, Haynes BF, Park S, Sasono P, Mlisana K, Salim AK, Hecht FM, Mulenga J, Chomba E, Hunter E, Allen S, Nemo G, Rodriguez-Chavez IR; Women's Interagency HIV Study Collaborative Study Group, Margolick JB; Multicenter AIDS Cohort Study (MACS), Golding H. HIV-SELECTEST EIA and Rapid Test: Utility for detection of seroconversion following acute HIV-1 infections. J. Clin. Microb. (2010); 48(1):281-85./>

External links frequently asked questions about HIV vaccine VISP Archived 26 July 2011 at the Wayback Machine

Worked examples

Example 1 — a first encounter with Vaccine-induced seropositivity

Start with the simplest possible case. Write down what Vaccine-induced seropositivity claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Vaccine-induced seropositivity before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Vaccine-induced seropositivity ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Vaccine-induced seropositivity

In research: Vaccine-induced seropositivity appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Vaccine-induced seropositivity in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Vaccine-induced seropositivity is common in secondary-school and first-year university syllabi. It links to neighbouring topics HIV/AIDS, HIV vaccine research, Vaccination, so understanding it makes those chapters shorter.
In everyday life: Look for Vaccine-induced seropositivity outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Vaccine-induced seropositivity in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Vaccine-induced seropositivity means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Vaccine-induced seropositivity out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Vaccine-induced seropositivity in simple terms?

Why does Vaccine-induced seropositivity matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Vaccine-induced seropositivity?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Vaccine-induced seropositivity.